This application discloses an invention which is related, generally and in various embodiments, to devices utilized for pipe inspection and a method of using the same.
Information from water and sewage pipes has immense environmental, civil, and commercial value. Often, such environments are space constrained and generally ill-suited for people to access and labor. In some instances, compact, sensory-tailored robotic systems are utilized to gather information associated with the pipe environment.
A variety of circumstances can cause the robot's performance to be less than adequate. For example, as illustrated in FIG. 1, robots 62 which utilize wheels 60 or narrow tracks often encounter debris 61 or other obstacles in the pipe 59 which the robot 62 is unable to navigating past or through. In many situations, the wheels 60 or narrow tracks of the robot 62 do not come in contact with the debris 61 in the center of the pipe 59. In such situations, the robot 62 is not able to climb over the debris 61 and continue its movement.
Also, as illustrated in FIG. 2, when robots 62 which utilize wheels 60 attempt to navigate past or through hard debris 61 or other obstacles in a pipe, the robot 62 can become immobile and stuck in a “high centered” position. Once the front of the robot 62 drives over the hard debris 61 or obstacle, the front wheels are often lifted and provide no traction for the robot 62. Additionally, as most of the robot weight is transferred directly to the debris 61 or obstacle, the rear wheels do not have much weight applied to them, and generally are unable to provide enough force to create any further movement of the robot 62 in the pipe 59. Robots which utilize narrow tracks generally experience similar problems when the debris or obstacle is positioned between the tracks, either in front of or below the body.
Robots which utilize a conventional track and pulley system often suffer from jamming of the track system 68, thereby rendering the robot immobile. As shown in FIG. 3, the pulley 69 generally defines a continuous series of teeth and valleys around the circumference of the pulley, and the track 70 defines a continuous series of teeth and valleys which cooperatively engage with teeth and valleys of the pulley. With this configuration, even small particulate can cause large problems. Any particulate that enters the system and settles in a valley of either the pulley or the track can cause meshing problems between the track and the pulley once the particulate reaches the pulley-track interface. The particulate in the valley operates to lift the track off of the pulley, thereby placing an increased tension on the track, requiring the motor to work harder and harder to move the track, and potentially causing the jamming of the track system.
In many configurations, compact robots utilized to explore, navigate, map, etc. include a winch mounted to the exterior of the robot. The winch is utilized to reel in the tether, thereby pulling the robot back towards its starting position. Because the tether often operates to carry power and/or control data to the robot, and data from the robot to a device external to the pipe for processing, the tether tends to be relatively large and heavy, thereby adding unnecessary size and weight to the robot. In addition, as shown in FIG. 4, the capstan is typically a flat-bottomed capstan which facilitates cable movement in only one direction. With the flat capstan profile, the tether often tends to walk to one side and become tangled as it is run continuously.
For exterior mounted winch configurations, odometry is traditionally performed by a mechanical counter in contact with the pulley so that the counter increments its count with each revolution of the pulley. In order to avoid corrosion and other problems with the counter, the winch typically requires that a seal be utilized to isolate the counter from the environment in the pipe.
Leaving a manhole cover in an open position for any length of time while the robot is gathering information can also result in the robot's performance being less than ideal. Inside typical underground pipe systems, the temperature is relatively constant (e.g., around 50 degrees Fahrenheit), and the humidity is relatively constant and relatively high. When a manholes cover is left in an open position, cold surface air typically enters the pipe, and a dense fog can form due to the relatively high temperature and humidity of the existing air in the pipe. The fog can be so dense that it can prevent proper visual observation of the pipe wall, thereby preventing some defects from being observed.